Oil leakage from cylinder head cover
- Safety Flash
- Published on 9 December 2021
- Generated on 20 March 2026
- IMCA SF 34/21
- 2 minute read
After completion of regular planned maintenance on one of the main engines, the cylinder covers were mounted back - however, the cover of cylinder number one was not mounted correctly and the guide pin of the cover was not in the recess of the cylinder head on the exhaust side (see figure 1 below).
What happened?
The misaligned mounted cover resulted in a small 3mm gap between cover and the sealing surface (see figure 3 below). This was not noticed at that time by the crew executing the regular maintenance as the gap is not visible from the walk platform side (cam-side).
The next day the main engines where started for departure and the regular checks were done, but the gap was not noticed.
figure 1
figure 2
figure 3
figure 4
What went wrong?
The gap was not noticed because the vessel had a slight list to starboard so the leaked oil was flowing from the cylinder head on the block in between the turbo charger and the regulator into the fuel oil leak tray (see image top right).
Only after the vessel made a turn to portside, did the duty engineer notice the oil leak (see image bottom right).
Actions
Investigation into the source of the leaked oil led to the discovery of the wrongly mounted cover. Quick action by losing the cover and giving it a gentle tap to make it fall back in its correct position, stopped the oil leakage.
The remaining spilled oil was quickly removed from the cylinder head and block.
The oil underneath the exhaust gas line was already starting to vaporise so quick removal of this oil was essential to prevent a possible fire.
After the clean-up, one of the engineers was assigned as a fire watch to check the exhaust gas line and engine.
The potential consequences of the oil leakage could have been an engine room fire.
Related Safety Flashes
-
IMCA SF 18/18
23 August 2018
-
-
IMCA SF 16/17
27 June 2017
-
-
IMCA SF 10/14
30 June 2014
-
IMCA SF 10/14
30 June 2014
-
IMCA SF 10/14
30 June 2014
-
IMCA SF 10/14
30 June 2014
IMCA Safety Flashes summarise key safety matters and incidents, allowing lessons to be more easily learnt for the benefit of the entire offshore industry.
The effectiveness of the IMCA Safety Flash system depends on the industry sharing information and so avoiding repeat incidents. Incidents are classified according to IOGP's Life Saving Rules.
All information is anonymised or sanitised, as appropriate, and warnings for graphic content included where possible.
IMCA makes every effort to ensure both the accuracy and reliability of the information shared, but is not be liable for any guidance and/or recommendation and/or statement herein contained.
The information contained in this document does not fulfil or replace any individual's or Member's legal, regulatory or other duties or obligations in respect of their operations. Individuals and Members remain solely responsible for the safe, lawful and proper conduct of their operations.
Share your safety incidents with IMCA online. Sign-up to receive Safety Flashes straight to your email.